You can use the subforum search feature, magnifying glass icon upper right, to find numerous discussions on how to downgrade the My Cloud firmware. In particular see the following thread which lists prior firmware.
Im usually quite quick at picking things up but if my Dad was to do this he would struggle, the dev team need to consider themselves as scientists ( explain things in simpler) / make it easier for people with no networking experience.
Mycloud products are fantastic for guys with a small amount of networking experience but for an end user its still tough to learn.
There are a number of ways in which WD have forgotten that their customers are not part of their development team, and may not understand WD’s adopted, non-standard terminology, or the systems surrounding the MyCloud that the MyCloud relies on.
I’m sure the user manual makes sense to the WD dev team, but it’s not always clear to the neophyte.
For instance, here are some comments from a year ago, when the latest manual was released: